For the most part sound, but:

• Uninformed optimisations
• Sometimes counterproductive

 What about those principles?

 Elephants in the room

Major performance issues were outside our direct control

• Advertising
• Fig.js

 Technical debt

Several of the hard things that are left to fix are technical debt

• Bloated JS
• Bloated CSS

Architecture choices that didn't scale

 Making the case

• Get hold of the best tools you can
• Identify metrics and KPIs that resonate
• Compare yourselves to the competition

 Raise awareness

• Make the work visible with dashboards
• Encourage performance champions
• Invite colleagues to LdnWebPerf ;)

 Be proactive

There's a limit to how much you can go back and fix later on.

Being reactive is:

• Fine for low hanging fruit
• Less so for intractable problems

Build a culture around performance.

 Make it sustainable

• Work with UX and designers
• Audience and analytics teams
• Set and share performance budgets
• Measure and act